1. Field of the Invention
The invention relates to a filter apparatus and more particularly to a self-cleaning, back-flushable filter for removing particulate material from a pump intake.
2. Description of the Related Art
Submersible pumps are often lowered into fluid supplies such as those found in well casings or ponds in order to remove the fluid that is found there. Often, the fluid contains sand and other abrasive particles that are a constant cause of inefficiency in and potential failure of the pumping systems. For example, sand can cause severe damage to the pump and valves in the pumping system.
Many types of filters have been designed for use with submersible pumps. Such filters have typically included a filter element designed to screen particulate material from the pump intake. However, the particulate material often becomes entrapped in the filter element. The quantity of particulate material collected on the filter element is directly proportional to the to the pressure drop that occurs across the filter element. Since an excessive pressure drop across the filter element can significantly reduce fluid flow, the filter element must be periodically changed or cleaned. Often, this is done by removing the submersible pump from the fluid and removing the filter element. This can be a timely and inconvenient process. Pumps with intricate backwashing systems have been designed, but these are often expensive and cannot be used to retrofit existing systems. As a result, many pumps are generally operated without any filter and therefore experience early pump failure and extensive and costly down time.
There exists, therefore, a continuing need for further improvements in fluid filter devices having a self-cleaning filter element. There further exists the need to have a relatively simple and reliable manner of backwashing filter elements used with an existing pump.
In one embodiment, the invention is a filter apparatus for use with a submersible pump. The filter apparatus includes a filter element, a supply line for delivery of a flushing medium, and a filter basket, wherein the filter element extends about at least a portion of the filter basket. The filter basket includes a manifold, including a flushing medium supply opening in a first surface thereof for receiving the supply line, a plurality of apertures in a second surface of the manifold, and an internal chamber fluidly connecting the flushing medium supply opening with the plurality of apertures. The filter basket also includes a plurality of tubes, wherein each tube of the plurality of tubes extends from one of the plurality of apertures and includes a plurality of perforations such that a flushing medium may flow from the supply line through the internal chamber into the plurality of tubes and through the perforations to backflush the filter element. The filter apparatus can further include a submersible pump with an electrical motor within the filter basket.
Another embodiment of the invention is a system for cleaning a filter apparatus used for screening the intake of a pump. The system includes a supply tank for storing a pressurized flushing medium, a supply line for delivery of the flushing medium, and a filter apparatus. The filter apparatus includes a filter element, a supply line for delivery of a flushing medium, and a filter basket, wherein the filter element extends about at least a portion of the filter basket. The filter basket includes a manifold, including a flushing medium supply opening in a first surface thereof for receiving the supply line, a plurality of apertures in a second surface of the manifold, and an internal chamber fluidly connecting the flushing medium supply opening with the plurality of apertures. The filter basket also includes a plurality of tubes, wherein each tube of the plurality of tubes extends from one of the plurality of apertures and includes a plurality of perforations such that a flushing medium may flow from the supply line through the internal chamber into the plurality of tubes and through the perforations to backflush the filter element. The filter apparatus can further include a submersible pump with an electrical motor within the filter basket.
Another embodiment of the invention is a method of flushing a filter apparatus used to screen the intake of a pump. The method includes encasing a pump suction inlet in a filter basket having a plurality of tubes, wherein each tube has at least one perforation therein. The method further includes surrounding at least a portion of the filter basket with a filter element such that a fluid to be pumped passes through the filter element to reach the pump suction inlet, and directing a flushing medium out of the perforations such that the flushing fluid is sprayed in an outwardly direction against interior surfaces of the filter element to dislodge or expel entrapped particulate material.